1. Technical Field
The present disclosure relates to network management and more specifically to handling audio traffic when the audio traffic approaches a committed data rate (CDR).
2. Introduction
In packet networks, packets can be marked for processing. Such markings can identify a packet as an audio packet, video packet, or data packet. Typically network infrastructure grants an audio packet the highest priority, followed by video packets and then data packets. A problem arises when the audio traffic approaches a committed data rate (CDR) for audio packets in the network. If the overall audio marked packet traffic exceeds the CDR for audio packets, then the network drops packets in excess of the CDR. Audio transmission quality is especially susceptible to dropped packets.
To avoid dropped audio packets, a packet network typically includes a Communications Manager (CM) responsible for management of the available audio bandwidth. The CM should be aware at all time of the number of audio sessions that are established and of the CDR for audio packets. When a call is attempted that would commit an amount of traffic that exceeds the CDR for audio packets, then the call is denied with a message that all circuits are busy. This process is called the Call Admission Control (CAC) process.
Unfortunately, the CM sometimes is informed that an audio session has been terminated when in fact the audio session improperly continues after termination has been reported to the CM. It also is possible for network devices to either intentionally miss-mark non-audio packets as audio packets for higher priority, or network devices can be mistakenly plugged in to the wrong part of the network causing non-audio packets to be marked as audio packets. In either case, the non-audio packets marked as audio packets use up a portion of the audio bandwidth of which the CM is unaware. When the audio traffic reaches the audio CDR, the CAC process continues to admit new audio sessions so that audio traffic exceeds the audio CDR and audio packets are dropped.